private void AddButton_Click(object sender, EventArgs e)
        {
            DataTable isSearch = _customerManager.SearchCustomer(nameTextBox.Text);

            if (isSearch.Rows.Count > 0)
            {
                //  customerDataGridView.DataSource = _customerManager.SearchCustomer(searchTextBox.Text);
                MessageBox.Show("Name Exists");
            }


            else
            {
                bool isAdded = _customerManager.AddInfo(nameTextBox.Text, contactTextBox.Text, addressTextBox.Text, itemComboBox.Text, Convert.ToInt32(quantityTextBox.Text));
                MessageBox.Show("Saved");
            }

            /* else
             * {
             *   MessageBox.Show("Not Saved");
             * }*/
        }